Mower decks have been designed that are convertible between a discharge or collection position and a mulching position. For example, U.S. Pat. No. 6,609,358 entitled “Mower Having a Mower Deck Adapted for Selective Mulching or Non-Mulching Modes” relates to a mower deck that can be converted between a discharge or collection position and a mulching position. The conversion may be done without using tools, and without separately attaching or detaching components on the deck. The convertible mower deck enables an operator to avoid the inconvenience of having to stop mowing to either remove or install a mulch kit. The convertible mower deck has adjustable gates between adjacent cutting chambers that can be moved to an open position in which grass clippings move between the cutting chambers and out through a discharge opening, or to a closed position in which grass clippings are mulched by restricting their movement between cutting chambers and blocking the discharge opening. The gates may be moved to either the open position or the closed position with a handle attached to the top surface of the deck.
U.S. Pat. No. 6,735,932 entitled “Variable Mulching System for a Lawnmower” and U.S. Pat. No. 6,751,937 entitled “Lawn Mower Discharge Shutter” relate to walk-behind mowers that may be converted between a discharge or collection position and a mulching position. The 932 patent relates to a plate that translates within the cutter housing, while the 937 patent relates to a shutter that rotates within the housing to adjust the size of the discharge opening. The mowers of these two patents are intended to allow mulching, discharging or bagging, or simultaneous mulching and discharging or collection in varying degrees. However, they are limited to walk behind mowers that include one blade in a single cutting chamber, and are not well suited for many large or commercial mowing applications such as mowing parks, highway medians and athletic fields.
There is a need for a convertible mower with multiple cutting blades that can mulch, discharge or collect grass clippings, or simultaneously mulch and collect or discharge grass clippings. There is a need for a convertible mower deck for large areas or other commercial mowing applications that can quickly and easily vary or change the amount of grass that is discharged or collected relative to the amount mulched. There is a need for a mower deck having multiple cutting blades that can simultaneously discharge or collect some of the grass clippings, and can mulch the remainder.